Invested around $15k into starting up my program, and only most of the paysites were already set up and had a nice backlog of content updates.
I would say you are probably looking at anywhere between $5k-20k depending on whether you have traffic, have affiliates, have design capabilities, what niche you are in, whether you are doing your own content, getting it shot, or loading your members areas with generic stuff, and around 100 other factors
NB. Without traffic and experience the odds are your paysite will be a tax writeoff.